ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Synthesis of DysidinThe synthesis of dysidin ((-)-1), the enantiomer of a metabolite of the marine sponge Dysidea herbacea, is described. To effect the synthesis, (±)-5-isopropyl-4-methoxy-3-pyrrolin-2-one (7) is converted to its lithium salt and reacted with (-)-(5R,2E)-3-methoxy-5-trichloromethyl-2-hexenoyl chloride ((-)-11) to give (-)-1 and its diastereoisomer (+)-5-epidysidin ((+)-12) epimeric at C(5) of the pyrrolinone ring. The (-)-acyl chloride (-)-11 has been synthesized from (+)-(R)-3-(trichloromethyl)butanoic acid ((+)-8) via the intermediates (+)-9 and (-)-10, the pyrrolinone 7 from N-benzyl-oxycarbonyl-L-valine via the intermediate 5. The enantiomers of acid 8 have been resolved by fractional crystallization of their diastereoisomeric N-(1-phenylethyl)amides. The (R)-chirality of (+)-8 was determined by comparing the 1H-NMR spectra of the diastereoisomeric N-(1-phenylethyl)amides 16 and 17, made from (+)-8 by substituting deuterium for chlorine, with the spectra of the N-(1-phenylethyl)amides 14 and 15 of known absolute configuration. This correlation shows that literature value (R) for (-)-8 is in error. Therefore, the structural formulae of (-)-dysidenin and (+)-isodysidenin, two other metabolites of D.herbacea, have to be changed to their mirror images as shown in formulae (-)-3 and (+)-4, respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19840670716
